1. Field
This disclosure relates generally to an improved immune serum globulin (ISG) preparation and specifically to an ISG preparation substantially free of existing prekallikrein activator (PKA) and PKA generated in time from a specific PKA precursor.
2. Prior Art
It is well known that the administration of ISG to patients with agammaglobulinemia has great clinical value in treating the complications of infectious disease. Unfortunately, the present route of intramuscular injection often severely limits the effective circulating levels of antibody which can be attained. In addition, direct intravenous injection of large doses of ISG is often not possible due to undesirable vasomotor responses which occasionally occur. The origin of this response is commonly attributed to the presence of IgG aggregates which bind complement and trigger an anaphylactoid reaction. The possible role of kinin system components has not been considered previously, although the presence of PKA in ISG has been pointed out.
To date, there has been no indication that any specific PKA precursors contributed to PKA activity in commercially available ISG solutions. Quite surprisingly is has now been found that both existing and potential PKA activity can be removed from ISG solutions by using ion exchange contact to remove both existing PKA activity and a kallikrein-activatable precursor to PKA previously not known to be present in such ISG solutions. Details of the ISG purification method and the product formed thereby are described below.